Elevator-brake.



(No Model.)

c. E. THUMAS. ELEVATOR BRAKE.

(Application filed June 29, 1901.)

Patented (lot. I, IQOI.

No. 683,624. Patented Oct. I, l90l.

' C. E. THOMAS.

ELEVATOR BRAKE.

(Application filed June 29, 1901.)

2 Sheets-Sheet 2,

(No Model.)

UNITED STATES PATENT OFFICE.

CHARLES E. THOMAS, OF CHICAGO, ILLINOIS.

ELEVA-TOR-BFiAKE.

SPECIFICATION forming part of Letters Patent N 0. 683,624, dated October 1, 1901.

Application filed June 29,1901, Serial No. 66,519. (No model To (all zvhont 111 may concern:

Be it known that I, CHARLES E. THOMAS, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Elevator-Brakes, of which the following is a specification.

My invention relates to elevators or hoisting devices of that class which is commonly used in connection with the erection of buildings for the purpose of raising building materials-as brick, mortar, stone, and thelikefrom the basement to the upper stories of the building. Devices of this character being temporary in their use in connection with the building with whichthey are employed and being designed to be moved from place to' place are necessarilysimple and more or less crude in their construction and lacking in which my present invention relates comprises in general a pair of cars disposed side by side and arranged to travel alternately up anddown between suitable vertical guides the frames of the cars being connected together by a singlecable which passes oversuitable guide-pulleys,whereby when poweris applied to said intermediate cable the cars necessaa stop on the level of the floor at which the material is to be delivered.

To this end my invention consists in a brake or stop mechanism associated with the guide- V which pulleys atihe top of the elevator-shaft and We which the hoistingcable runs, .all as hereinagter full y described, and more particularly pointed outii'r'the claims.

My invention in its preferred form is illustrated in the accompanying drawings, in

Figural is a perspective View of a portion of a building in course of erection, showing an elevator of the type referred to located therein and having the improvements constituting my present invention applied thereto.

Fig. 2 is a side elevation of the upper portion of the elevator mechanism and illustrating my improvements and their mode of application and operation in enlarged detail, and Fig. 3 is a top plan view of the parts shown in Fig. 2.

In the drawings, 4 indicates the basement, and 5, 0, and 7 the several floors, of a building in course of erection.

8 and 9 and 10 and 11 designate two pairs of vertical standards erected in the basement 4; and constituting guides for a pair of cars 12 and 13, respectively.

14.- and 15 designate vertical side members,

'and 16 a horizontal cross member, of a yoke disposed above and inf-the vertical plane of the guides 8 and 9 and 10 and 11, the uprights 14 and 15 resting upon the top floor 7 of the building and being suitably braced against lateral movement by oblique braces 17 and 18. The transverse member 16 of this yoke comprises two parallel horizontal beams, as shown'in Fig. 3, between which are suitably jonrnaled in the same vertical plane a pair of guide sheaves or pulleys 19 and 20,

said pulleys having V-shaped grooves in their peripheries over which operates the hoistingcable 21. This hoisting-cable 21 is secured at its two ends to the tops ofihe cars 12 and .85

13, as at 22 and 23, respectively, the intermediate portion of the cable passing over the guide-pulleys 19 and 20, as alreadystated, and also over a pair of guide-pulleys 24 and 25, located in vertical planes adjacent to the foot or base of the uprights 9 and 10, respectively, the said cable passing thence horizontally for a considerable distance along the floor of the basement 4, and finally passing around a horizontally-journaled guide-pulley 26, which may be secured in fixed position any suitable or desired manner.

The cars 12 and 13 being designed mpr'ely for the hoisting of building material are"- simply constructed, comprising, essentially, a horizontal platform and a suitably-braced vertical rectangular frame or yoke rising-- therefrom, as plainly shown in the drawings. The vertical side members ofthe frames-of the ears are grooved and slide overthe proximate faces of the guides in the elevation and descent of the cars, as plainly shown in Fig. 2. Temporary openings 27, formed through the several floors of the building, permit the passage of the cars ,therethrough, and the .elevation of the loaded car and the simultaneous descent of the empty car are efiected in the illustration of the device herein shown by means of horse-power applied to the cable 21, at a suitable hitch or cable-clamp 28 on the latter, the powerbeing applied alternately in opposite directions to efiect the alternate raising and lowering of the two cars.

Bnildingmaterial elevators constructed substantially as herein-above described are such as I have above described some means must be'provided for catching and holding the loaded car when it reaches the extreme of its upward movement, since otherwise the weight of the loaded carwould overbalance the smaller weight of the empty car, and as a result the loaded car would simply drop back, at the same time drawing up the empty car to the top of the shaft. Various devices for this purpose have heretofore been employed, that most commonly used being one or more books associated with the top frame or yoke in which the pulleys 19 and 20 are mounted and adapted to swing under and catch a cooperating member on the loaded car itself to thus hold the same elevated until the load has been removed and the car is ready to descend. Such devices have proved crude, awkward, and unreliable, besides requiring an undue amount of the operators time and attention to insure the proper working thereof. By

my present invention I have provided a simcar on a level, or substantially so, with the tively. A shaft 3i, mounted in plate 33, be-

tween the pawls 31 and 32, has an upstanding arm 35 fast thereon, the upper end of which is connected by links 36 and 37 with the pawls 31 and 32, respectively. :An' operating-arm I 38, fast on and depending from one end of the shaft 34, provides a means whereby through the connections described the pawls 31 and 32 may at the proper times be alternately shifted into and out of operative engagement with their respective ratchets. 1

v In view of the fact that the cars 12 and 13 are connected to the two ends of a common -intermediate operating-cable and must,

therefore, move simultaneously, one car as: cending while the other is descending, and" vice versa, it follows that if the rotation of the operating-cable on the several pulleys over which it isgnided. I have found that in practice all tendency of the cable to slip over its guide-pulleys may be obviated in an efiective manner by simply carrying the cable around either or both of the top guide- 'o pulleys 19 and 20- a sufficient number of turns to insure the requisite frictional contact of the cable with the pulley or pulleys, so'that such slip of the cable will be impos= sible under the heaviest loads designed to be carried by a car. I have found in practice that under the ordinary loads to which the cars are subjected it is amply sufficient in :order to produce this frictional effect to carry :the cable one and one-half times around each of the pnlleysl and 20. With such effective provision against the slip of the cable the travel of the cable and its attached cars .can be easily and simply controlled by a brake or stop mechanism applied to the pul leys lil'and 20, such as the pawl-and-ratchet device already described. 7

Y Referring now to the operation of the device in connection with my improvements and assuming thatlhe car 12, as shown in no Figs. 1 and 2, is a loaded car, the action of the mechanism and the manner of operating the same will be as follows; The operatingarm 38 is shown swung to the left, with the pawl 32 engaging itsratchet 30 and the com- 11 5 panion pawl 31 free from its ratchet 29. Such relative position of the'parts, together with the frictional engagement-of the operatingcable 21 with the pulleys l9 and 20, serves to hold the loaded car12 in its elevated position while the same is being unloaded and the empty car 13 at the foot of the shaft loaded. When these operations have taken place, the' operator swings the arm 38 to the right,withdrawing pawl 32 from ratchet 30 and throw ing the pawl 31 against ratchet 2 9. The sig- ..nai then being given to the operator in the 12 simultaneously descends by gravity, in

which dperation pawl 31 rides idly over the teeth of ratchet 29 until the empty car 12 This serves to ing-level.

have just reached its unloading-level.

touche's the bottom, whereupon the rotation of pulley 10 and ratchet 29 will cease and pawl 31 will drop into-locking engagement therewith, the cable 21 being of such a length that when one caris at the bottom ofrthe shaft the other will be exactly at the unloadrest in the basement, the loaded car 13 will If now it should happen that the application of the power to the cable should be continued slightly beyond this point, thus carrying the loaded car somewhat above its intended stopping-place, on the release of the power the loaded car will simply drop back until the cable has become taut to its proper unloading position on a level with the upper floor. It will be observed that this automatic ad'- justment of the loaded car to its proper registration with the level of the floor at which its load is to be discharged follows from the peculiar character and manner of operation of the pawl-and-ratchet mechanism, whereby the operative pawl is constantly kept in engagement with the pulley from which the descending empty car is suspended. This I regard as a matter of primary importance, sinceit etl'ects an automatic leveling of the loaded car in a manner that would not be possible werethe operative pawl to be kept in engagement with the ratchet pertaining to the loaded ascending car and to bite and hold such ratchet at the limit of the upward movement of the car,which might easily be either above or below the precise desired level, especially where horse-power is employed as the motive agent.

It will be observed that the shifting of the pawls 31 and 32 will take place each time a loaded and raised car has been unloaded and after the same has been unloaded, at which time the system will be in substantial equilibrium, owing-to the fact that both cars are empty, or in case the car at the bottom has already been loaded there will be no tendency to a backward rotation of the pulleys 19 and 20, owing to thesuperiorweightfof such loaded car. at such intermediate intervals when there is no loaded car suspended against the inadequate counterbalance ofan empty one I dispense with the necessity of a stop or brake device, which is required to become operative upon one pulley before or simultaneous with the release of its hold upon the other.

I do not wish to be understood as limiting my invention to the precise pawl-and-ratch'et form of brake or stop herein shown and described, since it is obvious that many other mechanical equivalent devices might be employed for the same purpose and to effect the same result. For instance, as'nitable friction brake or stop might in some cases be found adequate, while where the pawl-andratchet character of the stop is preserved the employment of a pair of pawls linked together,

. eachother.

When the empty car 12 hascom'e to By eifectingthe shifting of the pawls lated to and fro between the ratchets will depend on the proximity of the two ratchets to I wish it to be understood that such modifications would be fully within the spirit and scope of my invention, and the same is not limited thereto, except in so far as it may be defined'in specific claims herein appended. I

I claim as my invention- 1. In an elevator, the combination with a suitable supporting and guiding-frame and a pair of cars adaptedto travel simultaneously in opposite directions therein, of a single hoisting-cable conn-ectedat its opposite ends to said cars, a pair of guide-pulleys mounted in the top of the frame and above said cars respectively over which said cable passes, and a brake or stop device engaging said pulleys alternately to prevent backward rotation thereof when the-loaded cars alternately reach unloading position, substantially as described.

2. In an elevator, the combination with a suitable supporting and guiding frame and a pair of cars adapted to travel simultaneously tially as described.

3. In an elevator, the combination with a suitable-supporting and guiding frame and a pair of cars adapted to travel simultaneously in opposite directions therein, of a single hoisting-cable connected at its opposite ends IIO to said cars,a pair of guide-pulleys mounted in the top of the frame over which the end portions of said cable pass, and a brake or stop device adapted to become operative upon the pulley of the descending car when the latter reaches the bottom to prevent back-- waigl rotation of the pulleys under the tension of the elevated loaded car, substantially as described.

4. In a hoisting device of the characterde" scribed, the combination with a pair of T'cars adapted to be simultaneouslyoperatdjnop j i. I posi-te directions and a single hoisting-cable having its two endsconnectedtothe tops of said cars'respectively, of apair"of gifl'uide-pul-- leys suitably supported andjournaljedfabo've said carsv and having thehoisting-cable carried one and one-half turns around each,'-and an oscillating or shifting brake or stop device adapted to become operative upon the pulley of the descending car when the latter reaches the bottom to prevent f backward rotation of plurality of turns about each of said pulleys to secure increased friction thereon, a. rotary ratchet on the side of each pulley, and an intermediate pawl mechanism adapted to be thrown alternately into engagement with said ratchets, and normally engaging-the ratchetof the pulleyfrom which thedescendi'ng'em'pty caris suspended, substantially as described;- 6. In a hoisting device of the character described, the combination with a pair-of cars adapted to be operated simultaneously-in op;- posite directions, and a hoisting-cable connecting the frames ofssaid cars and having itsintermediate portion suitably guided and adapted for the application of power thereto, of a pair of guide-pulleys supported and journaled above said cars and having the end portions of the cable passed therearound with a plurality of turns to secure increased friction between the cable and the pulleys, a pair of circular ratchets on said pulleys, respec tively, a pairof pawlsipivoted between and 'adjacent said rate-bets, an operating; leverarm pivoted between said pawls, and links intermediate said lever-arm and pawls whereby said paw-ls are simultaneously oppositely operated,.s aid pawls and ratchets and their operati g mechanism constituting a stop or brake adapted to become operative in con gnection with the pulley of the descending car 40 when the latter reaches the bottom to sustain theleaded car in its elevated position through the intermediate portion of the cable and its 'guid'es,: substantially as described.

i CHARLES E. THOMAS.

. Witnesses SAMUEL N. POND, L. F; MCCREA. 

